MagicMock Returns different values each call

Recent discoveries about mock objects!

I'm trying to create a Python unittest that exercises a class method with a time() call in it.

That is I have this:

class DumObj(object):

  def methodOne(self, intime):

    while time.time() < intime:

      ... do stuff ...

so, I refactored this to:

class DumObj(object):

  def nowTime(self):

    return time.time() 

  def methodOne(self, intime):

    while self.nowTime() < intime:

      ... do stuff ...

and have to test methodOne. How to get it to go through the loop once (or twice)?

I tried setting the return value to the output of a function:

import unittest

from mock import Mock, MagicMock

class TestDumObj(unittest.TestCase) 

 def test_methodOne(self):

 d = DumObj()

    retvals=[1,2,3,4,5] 

    def mf():

      ret = retvals.pop()

      return ret

 d.nowTime = MagicMock(return_value=mf()) d.methodOne()

Doesn't work. Here's the interactive version:

>>> from mock import MagicMock

>>> retvals = [ 1, 2, 3, 4, 5 ] 

>>> def mse(*args, **kwargs):

... ret = retvals.pop()

... return ret

... 

>>> mm = MagicMock(return_value=mse())

>>> mm()

5

>>> mm()

5

Damn! I want MagicMock to return different values each time it's called. I want to have an array of return values for MagicMock, and each call it returns the next one. How to do this? Turns out it's using the side_effect param. Continuing from above:

>>> mm = MagicMock(side_effect=mse)

>>> mm()

4

>>> mm()

3

Yay! Solved: MagicMock returns different values each call. Now, tie it into the overall test:

import unittest

from mock import Mock, MagicMock

class TestDumObj(unittest.TestCase) 

 def test_methodOne(self):

 d = DumObj()

    retvals=[1,2,3,4,5] 

    def mse():

      ret = retvals.pop()

      return ret

 d.nowTime = MagicMock(side_effect=mse) d.methodOne()

Works!